Wireless local area networks (WLANs) conforming to specifications in the Institute of Electrical and Electronics Engineers (“IEEE”) 802.11 family typically involve an infrastructure-based network topology such as a basic service set (BSS) or an ad hoc-based network topology such as an independent basic service set (IBSS). While a BSS may be managed by a device acting in the role of an access point (AP), management functions in an IBSS are distributed among the participating devices. One important area associated with network management is the implementation of power management techniques that allow a device to enter a power save mode of operation, during which it may be able to conserve battery resources, but may not be able to receive or transmit communications. Such techniques may be more challenging in an ad hoc network due to the lack of a dedicated management device, such as the AP.
To that end, power management for stations operating in an IBSS may be coordinated through the use of announcement traffic indication messages (ATIMs) that are exchanged during a defined period of time known as the ATIM window that immediately follows the target beacon transmission time (TBTT). Conventionally, all stations in the IBSS awaken prior to the TBTT in order to receive the beacon transmission and stay awake at least for the duration of the ATIM window. Accordingly, a station may send an ATIM frame within the ATIM window to indicate the presence of buffered data that is pending transmission to one or more other stations. Upon receipt of an ATIM frame identifying it, a station may then remain in active mode through the current beacon interval in order to receive the buffered data. Likewise, the station having buffered data also remains in active mode to transmit the data during the current beacon interval.
As will be appreciated, this conventional scheme results in all stations in the IBSS remaining in active mode for the duration of the ATIM window. Further, any station that will be transmitting or receiving buffered data remains in active mode for the current beacon interval and at least the subsequent ATIM window. Thus, considerable power is expended by the stations in order to operate in active mode for the ATIM windows and additional power may be consumed when buffered data is to be exchanged.
Accordingly, it would be desirable to provide systems and methods for coordinating power management among devices in an IBSS that allow a reduction in power consumption while coordinating the exchange of buffered data. This disclosure addresses these and other needs.